Clinical measurements have been traditionally carried out in central clinical labs using large clinical analyzers that can handle large numbers of samples in batch mode. These laboratories are staffed by trained personnel that are capable of maintaining and running these complex analyzers. There is a growing desire to move clinical measurements from the central lab to the “point of care”, e.g., the emergency room, hospital bedside, physicians office, home, etc. Point of care measurements allow a care provider or patient to quickly make decisions based on diagnostic information, as opposed to having to wait hours or days to receive laboratory results from a clinical lab. The difficulty in developing point of care diagnostic systems has been making them small enough and easy enough to use so that they can be used by unskilled operators in decentralized clinical settings, but at the same time maintaining the low cost, diverse assay menu, and/or high performance of tests carried out on traditional clinical analyzers in central laboratories.
In addition, certain types of tests carried out in point of care diagnostic systems involve a series of complex processes that can be hampered by the presence of contaminants in the system. For certain types of tests, e.g., polymerase chain reaction (PCR), the allowable levels of contamination are very low, typically one part in 10,000. There is a need for a point of care system that can conduct complex multi-step processes with minimal contamination from one step to the next.